Chromatographic detection apparatus

ABSTRACT

APPARATUS FOR CHROMATOGRAPHIC DETECTION INCLUDING MEANS FOR TRANSFERRING A PHASE SEPARATED IN A CHROMATOGRAPHIC COLUMN FROM SAID COLUMN TO A DETECTOR; THE TRANSFERRING MEANS COMPRISES A ROTATING BODY WITH A COLLECTING SURFACE RECEIVING THE SEPARATED PHASE FROM THE COLUMN AND CONVEYING IT TO THE DETECTOR FOR EVALUATION.

July 10,1973 H.DUBSKY I 3,744,973

CHROMATOGRAPHI C DETECT ION APPARATUS Filed Aug. 11, 1971 2 Sheets-Sheet l 4 INVENTOR: HANNIEL DUBS'KY ATTORNEY July 10, 1973 H. DUBSKY CHROMATOGHAPHIC DETECTION M'PAHA'IUS 2 Sheets-Sheet 5 Filed Aug. 11, 1971 INVENTOR 1 HANNIEL ouasxy BY:

ATTORNEY United States Patent 3,744,973 CHROMATOGRAPHIC DETECTION APPARATIE Hanniel Dubsky, Brno, Glzeehoslovakin, assignor to Ceskoslovenska akadernie ved, Prague, Czechoslovakia Filed Aug. 11, 19711, Ser. No. 376,759 Claims priority, application Czechoslovakia,

Aug. ll, 1976, 5,589/70 Int. (Ii. Gllln 31/12 US. Cl. Z3-254 BF 9 Claims ABSTRACT OF 'IHE DESCLOURE Apparatus for chromatographic detection including means for transferring a phase separated in a chromatographic column from said column to a detector; the transferring means comprises a rotating body with a collecting surface receiving the separated phase from the column and conveying it to the detector for evaluation.

BACKGROUND OF THE INVENTION This invention relates to an arrangement for transfer of material for chromatographic detection, particularly for liquid or gas chromatography.

Liquid chromatography is applied primarily for analysis of material which cannot be gasified, gas chromatog raphy is applied for analysis of material which can be gasified or converted to vapours. Both these methods require an arrangement which transfers the analysed material after separation to fractions from the chromatographic column to the detector, in which detector the fractions are evaluated. The most sensitive device for this purpose is at present the so called wire chromatograph with ionisation detection.

A supporting wire is used in such device, on which a solution-the fraction with a mobile phaseis applied. This solution wets the wire, a part of the solution sticks to the wire, the substantially major part of the solution, however, is discharged. The part of the solution which sticks to the wire enters in the course of movement of the wire, the evaporating space where the mobile phase evaporates and the fraction remains on the wire, to enter subsequently a pyrolytic tube, where at high temperature in an inert atmosphere the rest of the fraction is disintegrated to smaller volatile pyrolytic product. A part of these products escapes through the ports for the passage of the wire, and the rest passes into a flame ionizing detector, causing changes of ionisation, which changes are registered and evaluated.

Another method, where the fraction is directly burned on the wire passing through the detector, is less advantageous because of low sensitivity and noise. A drawback of both methods is that the supporting wire must be of relatively small cross section in order to enable its rewinding, what is a substantial disadvantage, as it has a small supporting surface on which the mobile phase with the fraction is applied. Another drawback of the Wire transfer is that it does not give quantitative results, and the major part of the solution is wasted. A further drawback is the possibility of breaking the wire.

SUMMARY OF THE INVENTION It is an object of this invention to provide a relatively simple and efiicient transfer of the measured material, for instance of a liquid from the chromatographic column to the detector, so that even quantitative results could be obtained.

It is a further object to enable additions of impregnating material in the course of the process.

The arrangement according to this invention comprises a rotating body provided with a heated collecting surface for the transferred material, said collecting surface being ,744373 Patented July 10, 1973 either below or above the outlet from the chromatographic column and passing into the ionising detector.

DESCRIPTION OF THE DRAWINGS DESCRIPTION OF PREFERRED EMBODIMENTS With reference to the embodiment of FIGS. 1 and 2, the arrangement comprises a rotating body 1 fixed on a shaft 2 which is, driven by a driving motor 4. The circumference of the rotating body 1 extends into a disk shaped collecting body 3, which in the course of operation is heated either directly by electric current as a resistor, or indirectly by a gas flame, or by any other known manner. In the given case the collecting body 3 is heated by infrared radiation from a bulb 8. A chomatographic column 5 and a detector 6 are provided above the disk shaped collecting body 3, the detector 6 having two electrodes 7, to the terminals lit and 11 of which there is connected the evaluating device of the chromatograph.

FIGS. 3 and 4 show another arrangement, Where the collecting body 3 has the shape of a cylindrical mantle. The container 9 indicated by broken lines serves for dosing impregnating material on the surface of the collecting body 3.

The arrangement according to this invention operates as follows:

The driving motor 4 transmits to the shaft 2 and to the rotating body 1 connected therewith a rotating motion in the direction of the arrow. Samples of the mobile phase with the investigated fraction, drop from the chro matographic column 5 to the surface of the collecting body 3, where they settle or are absorbed. Alternatively, some impregnating material is simultaneously applied from the container 9. As some parts of the collecting body 3 are heated to a predetermined temperature, the mobile phase of the sample evaporates before the sample reaches the detector 6. Here the remaining fraction is burned and the generated gases produce changes of ionization between the electrodes 7. These changes are registered and evaluated in the evaluation device, connected to the terminals 10 and 111.

An advantage of the arrangement according to this invention is that the rotating collecting body 3 can be made of any suitable material which is most advantageous for the investigated material, an advantage which is impossible when using a Wire for the transfer. As suitable material for the collecting body, either a sheet with a rough surface or a grid can be used. For some samples porous material, for instance ceramic material, is advantageous. Good results have been obtained with quartz grids. A disk-shaped collecting body 3 has the further advantage that some impregnating material, for instance a catalyst accelerating the burning of the sample, which catalyst can for instance absorb the sample such as cobalt oxides and the like, can be applied in a relatively simple manner on the collecting body 3.

A thermoionisation detector can be easily provided with this arrangement when applying continuously some alkaline metal salt on the collecting body 3 from a container. A thus arranged detector surpasses actually known types in performance and has a constant sensitivity.

The arrangement furthermore enables the use of any suitable shapes of electrodes 7 of the detector 6. Both electrodes 7 can be, for instance, above the grid of the collecting body 3 as shown in FIGS. 1 to 4. Alternatively the burner of the detector 6 may form one electrode 7, the second electrode 7 being above the grid, or one electrode 7 may be the collecting body 3 itself. A higher sensitivity can be obtained by using two burners of the detector 6 and two couples of electrodes 7. By means of this arrangement, it is possible also to achieve, for one fraction by flame ionisation, a thermoionisation detection. If the outlets from the chromatographic column are "arranged so that the samples are applied on the collecting body 3 as two bands, two independent detection systems can be used.

As an example of the application of the invention a disk shaped collecting body 3 having an external diameter of 8 cm. has been used, the collecting body 3 being of either metallic or non metallic material. The sample has been applied from the chromatographic column 5 not as a film, but in drops. As mobile phases, alcohol, acetone, hexane, gasoline, and water have been used. As fractions of the sample, sugar, squalen and condensed aromatic material have been used. The sample of the material has always been completely burned without residues. The same arrangement has been used for gas chromatography. For instance acetylacetonate has been determined by heating a sample of aluminium acetylacetonate in a tube, and by taking along the vapours by a stream of argon to strike the collecting body 3 when they are condensing. It has not been necessary to remove the residue after burning the sample.

The arrangement can be furthermore provided with means for cleaning, washing or also cooling the collecting body 3.

4 I claim: 1. Chromatographic detection apparatus comprising a chromatographic column, a rotatable transfer device comprising a means having a rotary surface positioned to receive samples discharged from said column, said rotary surface being provided at its sample contact area with a catalyst to promote the production of gas from the sample, a flame ionizing detector, and means for rotating said transfer device to transfer the sample carried on the rotary surface from the column to the detector.

2. An arrangement as in claim 1, the collecting body having the shape of a disk.

3. An arrangement as in claim 1, the collecting body having the shape of a cylindrical mantle.

4. An arrangement as in claim 1, the collecting body being a grid.

5. An arrangement as in claim 1, being of metal.

6. An arrangement as in claim 1, being of non-metallic material.

7. An arrangement as in claim 1, being of ceramic material.

8. An arrangement as in claim 1, being a quartz grid.

9. An arrangement as in claim 1, comprising furthermore a container for discharging said catalyst of the collecting body.

the collecting body the collecting body the collecting 'body the collecting body References (Jited UNITED STATES PATENTS 3,419,359 12/1968 Anderson et al. 23232 EX 3,566,677 3/1971 Cole et al 23254 EF MORRIS O. WOLK, Primary Examiner R. M. REESE, Assistant Examiner 

